this was pulled out of Rails 4, see rails/rails#8399 for the discussion

if there's content for the right column, then we need the two-column class, if not the one-column

change useless gsub to tr

Assigning '0.0' to a nullable numeric column does not make it dirty

Example:
    product = Product.create price: 0.0
    product.price = '0.0'
    product.changed? # => false (this used to return true)
    product.changes # => {} (this used to return { price: [0.0, 0.0] })

Routing match `via` option requirement exception message made more explicit

Change useless gsub to delete

strong parameters example for default values using `fetch`.

Closes #9558.

Origin: #9534.

Use 1.9 String#gsub syntax

When the Rails 4 gem is installed rdoc sees markdown files below the
guides directory and processes them. With an empty .document file
we prevent that from happening. Thanks to @drbrain for the tip.

`ActiveRecord::Base.include_root_in_json` is `false` by default.

Closes #9459.

The PR #6597 unified the configuration for `include_root_in_json`
in AM and AR to `false`.
Later on with the refactoring commit: e030f26a the value in AR was
set to `true` but I think this was not on purpose.

With this commit both AM and AR will have the same configuration
for `include_root_in_json`, which is `false`.

Fix formats on xhr requests when HTTP_ACCEPT is empty string

Fixed typo in active record's changelog

Fix ActionDispatch::Request#formats on xhr requests when HTTP_ACCEPT
header is empty string. About issue #7774, same fix as in commit bebb02fd
but for xhr requests.

add prompt to 422 page to check logs

Introduce relation #unscope

In example fix sql that is generated from scoping